Immunosensor for breast cancer CD44 biomarker detection based on exfoliated graphene quantum dots integrated gold nanoparticles

Abstract

Breast cancer is a fatal disease caused by the abnormal development of cells in the breast, which forms tumors, and whose progression results in metastatic behavior. In this study, we present a novel electrochemical immunosensor based on graphene quantum dots decorated gold nanoparticles (GQDs-GNPs) for the early detection of breast cancer antigen Cluster of Differentiation-44 (CD44). The GQDs have been synthesized through electrochemical exfoliation of waste dry cell batteries and a simple chemical process was employed for the synthesis of GQDs-GNPs nanocomposite. It has been characterized for its electrochemical properties. The immunosensor was created utilizing GQDs-GNPs nanocomposite cross-linked via EDC/NHS coupling procedure to immobilize anti-CD44 antibodies. The resultant electrode surface was characterized by Transmission Electron Microscopy (TEM), Cyclic Voltammetry (CV), Differential Pulse Voltammetry (DPV), and Electrochemical Impedance Spectroscopy (EIS). TEM analysis revealed an average spherical GQD size of 3 nm and a GNP size of 15 nm. In phosphate buffer saline (PBS), the immunosensor had a low detection limit of 1.17 fg/mL. The findings suggest that the generated GQDs-GNPs nanocomposite exhibits favorable properties for usage as a successful nanomaterial in biosensing and other applications. According to these findings, our newly built immunosensor has a lot of potential to be a valuable alternative diagnostic tool for identifying various cancer biomarkers, particularly CD44 that exist in biological materials. The results indicate that the synthesized GQDs-GNPs nanocomposite possesses desirable properties for use as an effective nanomaterial in biosensing and other applications.